Improve deployment index page
### Description
This was issued out from https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/22380#note_110110835
Today, we have deployment index page. It looks like

Here is a couple of thoughts from @dimitrieh
> - Real time updating of the list (so deployments go from deploying => deployed similar to pipeline list view or merge request widget)
> - "Deploying" badge
> - removal of action buttons when the row represents a deploying deployment
> - env Stop button disabled when there is a deployment in progress
issue